>>11005970That Black Series figure has single knees too, like other recent figures in the line, but yeah, what you say sometimes happens.
The leg has more space for two joints, it's often clothed so the joints are not on bare skin (can look like folds or creases), and it also has the "closed" outer side of the joint facing forward which doesn't look as bad as the inner side.
Pictured: double jointed knees and elbows on a 4" figure, with the double jointed elbows being much more visually noticeable than the knees.
